In March of 1562, the Duke of Guise whipped his forces together and descended on a Protestant service in Champagne. All worshippers were killed; estimates range from 100 to 1,000 dead. The Bourbons and the Montmorency-Chatillons declared war.

Catherine de Medici consulted her 'Ruling France... for Dummies' book (inspired by this Machiavelli guy, apparently) and decided that if the three families were too caught up in killing one another, they would forget all about her, and she could rule in peace. She set about on keeping the families at each other's throats, which by and large worked, until August 1572.